Re: [avr-chat] ATmega88 + triple 7 Segment Display (CC)

[Dustin Lang]

The triple 7-segment display probably has a single pin for each of the 
seven segments, wired in parallel to the three digits.  Then instead of 
one GND, it will have one for each digit.  Get out your multimeter, put it 
on the diode setting, and check.  If that's how it's set up, then you'll 
need to repeatedly loop through the digits to refresh them.  (Indeed, 
timers that appear in TV shows need to be specially built to not work this 
way!)

If I were you, I'd probably wire 7 of the 8 PORTD pins to the seven 
segments, and three of one of the other ports to the GND pins.  But you 
should check how much current it will need to sink when all seven segments 
are on - you might need a transistor to handle the load.

Cheers,
dstn.


On Wed, 27 Feb 2008, Student1 wrote:

> Hi,
> I've completed a circuit for an ATmega88 that is to be programmed through
> Serial Port. I've tested it with LED and now I want to hook up a triple 7
> segment display (common cathode) to give it a 10 minute counter. 000 to 959
> (before resetting).
>
> So my question is, now that I have purchased a 7 segment CC, how do I do the
> circuitry to attach it to the AVR properly. From what I have seen, a single
> 7 segment display has 10 inputs (2x GND, A->G, dp). My triple 7 segment
> displays has 11 pins on it.
>
> And from looking at the ATmega88 specs sheets, it has 6 PORTB, 6 PORTC, 8
> PORTD which I can use for programming. Although PORTB0 is for input capture
> for timer/counter (what does this mean?).
>
> [img]http://img120.imageshack.us/img120/2598/img0820kf7.jpg[/img]
> http://img120.imageshack.us/img120/2598/img0820kf7.jpg
> [img]http://img101.imageshack.us/img101/892/img0822ot6.jpg[/img]
> http://img101.imageshack.us/img101/892/img0822ot6.jpg
>
> After I get this done, the next part will be working on the programming.
> Hopefully a lot of the capabilities from the delay program will work for
> this one.
>
> Thanks
>
> Maybe I should add the 7 Segment CC P/N is LEDSM-314220 (although an online
> search turned up nothing). It says RGE30361LP on the side as well.
>
> On the back 6 pins at top and 5 points at bottom.
>
>
> --
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> http://www.nabble.com/ATmega88-%2B-triple-7-Segment-Display-%28CC%29-tp15708386p15708386.html
> Sent from the AVR - General mailing list archive at Nabble.com.
>
>
>
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